Boxing is one of the most brutal professional sports in the world. Fighters are paid big money to literally knock each other senseless.
Boxing great Muhammad Ali has been diagnosed with Parkinson's disease—a brain disease—since his retirement. Those who regularly suffer from severe head trauma, such as boxers, are especially vulnerable to this illness.
In such a combative sport, is there really a need for extra foul play? Almost every fighter has thrown a low blow or head-butted his opponent in a fight before, but this list puts a spotlight on the notorious cheaters.
These boxers used dirty tactics as part of their arsenal, and some of their legacies are even defined by it.